Ocular non-Hodgkin's lymphoma is a rare condition that can involve the retina, the vitreous and the optic nerve. It can occur alone or can be associated with lymphoma of the central nervous system and a frequent manifestation is a posterior uveitis of difficult treatment. This kind of ocular tumor is difficult and a challenge to diagnosis. We describe a case of non-Hodgkin's intraocular B-cell lymphoma in a 47-year-old woman who had a posterior uveitis as the first manifestation. We emphasize the importance of a careful investigation and of the general clinical examination since this is the most common type in the eye. We expect to call the attention to this disease that many times appears in an unspecific form with unspecific symptoms.